A review of flow-induced vibrations in reactors and reactor components

This paper provides a brief overview of progress in our understanding of flow-induced vibration in power and process plant components. The flow excitation mechanisms considered are turbulence, vorticity shedding, fluidelastic instability, axial flows, and two-phase flows. Numerous references are provided along with suggestions for future research on unresolved issues.

Flow-Induced Vibrations in Power and Process Plant Components—Progress and Prospects

On the stability of heat exchanger tube bundles, part I: Modified theoretical model

A generalization of the quasi-steady theory is proposed, the aim of which is to model the most important unsteady effects neglected by the conventional quasi-steady assumption. Although this generalized model, referred to as the quasi-unsteady model, can be applied in a vast range of flow-induced vibration problems, including classical aeroelasticity, it was primarily developed to improve the theoretical prediction of the fluidelastic behaviour of a single flexible cylinder positioned in the midst of an array of rigid cylinders. In this context, it is shown that the previous improvement to the quasi-steady theory proposed by Price & Paidoussis can be considered as a particular case of the quasi-unsteady model. Results obtained with the quasi-unsteady model are compared to experimental data and to solutions from the Price & Paidoussis model; both modal parameter variation with flow velocity and stability diagrams are considered. This comparison shows that the quasi-unsteady model is a clear improvement on Price & Paidoussis’ approach, leading to a more reasonable agreement with experimental results and providing refined insights into the physical mechanisms responsible for fluidelastic instability.

An improvement to the quasi-steady model with application to cross-flow-induced vibration of tube arrays

Guidelines for the instability flow velocity of tube arrays in crossflow

Tube arrays in cross flow start to vibrate abruptly when the flow reaches at a certain velocity. The threshold flow velocity depends upon the geometrical arrangement of tubes. It is very important for practical applications to understand the relations between the threshold velocity and pitch-to-diameter ratio of tube array. Unsteady fluid dynamic forces on a tube array with a pitch-to-diameter ratio of 2.0 were clarified experimentally and the characteristics of the threshold velocity were revealed by calculating the velocity with the unsteady forces. By comparing the threshold velocities of tube arrays of pitch-to-diameter ratio of 2.0 and 1.33, the characteristics of threshold velocity with respect to pitch-to-diameter ratio were clarified.

Flow-Induced Vibration of Tube Arrays With Various Pitch-to-Diameter Ratios

This paper presents a method to calculate the critical flow velocity of fluidelastic vibration of tube arrays in heat exchangers. The method is based upon the modal analysis technique, which combines the fluid dynamic force caused by cross flow and the vibration characteristics of the complicated tube array to obtain its response. The analytical method enables us not only to take into account the vibration mode of tube array and nonuniformity of velocity and density distribution of cross flow, but also to estimate the effect of antivibration devices, such as spacer, connecting band, and so on. Numerical examples of constrained single-tube array, multi-tube array in reversed flow, and group of panels with spacers are described.

K. Ohta

Papers

Flow-Induced Vibration of Tube Arrays With Various Pitch-to-Diameter Ratios

Study on the Fluidelastic Vibration of Tube Arrays Using Modal Analysis Technique